Simple past tense and past participle of co-chair.(verb)
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Use "co-chaired" in a sentence
"A version of this idea has been advanced by a group of experts that was convened by the American Foreign Policy Project and co-chaired by former Ambassador Thomas Pickering and the aforementioned Gary Sick."
"A friend, confidante and adviser to both Barack and Michelle Obama for more than two decades, Jarrett, 54, followed them to Washington, D.C., after the 2008 election and co-chaired Obama's transition team."
"Leaders of the PPP, co-chaired by Pakistan President Asif Ali Zardari, say they don't believe the army would go as far as a coup to unseat the government."